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HEVs vs PHEVs vs BEVs

Discussion in 'Electric Vehicles' started by TEG, Dec 7, 2007.

  1. TEG

    TEG TMC Moderator

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    [ This is just recap for a lot of us. This post is more for 'newbies' to the forum. ]

    So far, Tesla has been a company dedicated to 100% BEVs ("Battery Electric Vehicles").

    Recently, much of the world has embraced HEVs ("Hybrid gas/Electric Vehicles") such as the Toyota Prius.

    Along with Tesla's BEV push, some other companies have been trying to ramp up PHEVs ("Plug-in Hybrid Electric Vehicles")

    All of these vehicles have batteries and an electric motor.
    One way in which they all differ is battery capacity and all electric range.

    A typical HEV might have a 2 kWh battery pack and could go a couple of miles on full electric, so it would be rather dependent on the gas engine. Also they tend to have low output electric motors, so highway driving requires the gas engine to be on most of the time.

    A typical PHEV might have a 15kWh battery pack and could go approx 20 miles on all electric. This would be enough for many people's commutes, and if you can plug in at work, you get many of the benefits of a BEV, but with the freedom to drive beyond your electric only range at will.

    To have a useful range, a full BEV typically needs 30+kWh of battery capacity.

    Tesla has shown hints that it may be thinking of branching out from BEVs to PHEVs. One big reason why this does make sense is battery price. When Tesla first started up there was a sense that major battery (and/or ultracapacitor) breakthroughs were just around the corner, but we have yet to see those turn into real production ready opportunities. If we throw out a (very) ballpark number of $500/kWh for today's batteries you see that a typical HEVs (like the Prius) only has an incremental additional expense to include their limited pack (but they get the nice benefits of regen braking, and gas engine shutdown at stoplights).
    A PHEV could add $8000+ in batteries, which would be a hard sell for a mainstream economy car, but could be absorbed in a $50K luxury sedan.
    Full highway capable BEVs still need $16000+ in batteries to have a useful range. That is a lot of cost to tack on to get a vehicle and still make it competitive to sell at a profit.

    This forums is meant to be all about BEVs. They are the most elegant solution. But cost is a big hurdle, and all the BEV companies are going to struggle with this fact until we get more battery breakthroughs. I have been very against Tesla going the PHEV path, but if it is the only way to stay in business long enough to be ready when the battery prices come down enuogh then so be it.
     
  2. AGR

    AGR Member

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    TEG,

    Thank You for refreshing everyone's memory about the different variations of "electric".

    The Tesla BEV solution works on a low production specialty vehicle, the Roadster is that vehicle.

    The parellel hybrid solution from Toyota be it a Prius or Camry is primarily an ICE powered vehicle with an electric assist, its a step in the right direction. Toyota is cautious with the batteries, and the initial hybrid premium no longer applies, the average consumer is not prepared to pay a huge premium for an electric or hybrid vehicle.

    GM having learned some lessons with the original EV1, I think the volt is a series hybrid am I correct? This car must be priced to have mass appeal, small ICE with small batteries, innivative styling to set it apart, or immediately identify it as different. If you can plug it in people will start getting used to charging vehicles, but not get stuck if they cannot charge it.

    Which direction will Tesla take? They have highly paid individuals to make those decisions, by now they should know.
     
  3. TEG

    TEG TMC Moderator

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    #3 TEG, Dec 7, 2007
    Last edited: Dec 8, 2007
    The current Volt concept car is a "series hybrid" (in spite of it being a "so called BEV with range extending generator").
    As far as I can tell it was just a research project within GM until Tesla started drumming up so much excitement. GM decided to hype their Volt project to capture some of the attention that was headed Tesla's way. For whatever reason, Tesla people have been quoted recently as saying that the Volt is a good idea. In fact calling it "elegant" which is not what the Tesla of a year ago was saying.

    Also as far as I can tell, the Volt concept was really just their fuel cell research platform and they slapped in a small gas engine (instead of the fuel cell) when public sentiments swayed towards gas-electric hybrids instead of fuel cell research.

    The whole situation seems a little surreal and bizarre to me right now. We have various desperate companies running their spin machines with uncertain underlying motivations. The Tesla of a year ago seemed narrow minded and focused on a particular goal. The Tesla of right now seems evasive. Other hints dropped by them suggest that we will soon see some sort of announcement of a "new, improved business plan" with some sort of major deal involved. I am trying not to speculate what this might be.
     
  4. tonybelding

    tonybelding Active Member

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    #4 tonybelding, Dec 7, 2007
    Last edited by a moderator: Dec 7, 2007
    Huh? Whaa?

    I thought GM said it's not any kind of hybrid! It's a 100% pure electric car.

    Which happens to have a "range extender".

    Which happens to burn gasoline. :tongue:
     
  5. mt2

    mt2 Member

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    Ohhhh! Here, and I was telling everyone it was a hybrid. My apologies, Mr. Lutz.
     

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